An acoustic analysis of English-majored students’ errors in pronouncing plural nouns and third-person singular simple-present verbs: A case study

Abstract

This quantitative study examines how 25 Vietnamese university English majors pronounce the word-final /s/ or /z/ in plurals and third-person singular simple-present verbs. Recruited via convenience and stratified samplings, the students completed three speaking tasks, producing 2,136 tokens for analysis and revealing two primary error types: dropping (74%) and mispronouncing (26%). Acoustic analysis using Praat (waveforms, spectrograms, spectral slices) interpreted that systematic mispronunciations often traceable to erroneous patterns in penultimate sounds. By providing an acoustic-phonetic diagnostic basis and concrete instructional strategies, the study empowers TESOL teachers with evidence-based practices to detect and assess word-final /s/ and /z/ errors hardly perceived by human ears, and remediate them, thereby improving accuracy and fluency in speaking English as a foreign language.